The Blair Cuspids: A Mystery Revisited

Lan Fleming

LanFleming@aol.com

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In 1966, NASA released a photograph taken by Lunar Orbiter 2 of a
region on the western edge of the Sea of Tranquility that showed
several objects casting unusually long shadows. A few scientists
at the time speculated that the shadows were too elongated to be
cast by common lunar boulders or ridges. Among them was William
Blair, reportedly of the Boeing Institute of of Biotechnology.
Blair noted that the objects casting these shadows appeared to be
arranged in a subtly regular fashion that, together with the
seemingly anomalous height of the objects, suggested an artificial
origin. These objects came to be known as the Blair Cuspids. While
there is some evidence that NASA was at first interested in the
unorthodox possibilities raised by Mr. Blair and others, an
official explanation was quickly settled upon that attributed the
elongated shadows to a very low sun angle. A brief account of the
discovery of the Blair Cuspids and how they came to be dismissed
as the product of "uncritical" thinking is
here.

When the photograph was released, the NASA public affairs office
identified it according to a numbering system that has since
become obsolete, so there was no way authenticate the image or to
access the photographic support data listing the sun angle at the
time and place of the photograph. This information on the
illumination geometry is of critical importance in evaluating the
validity of the official explanation of why the shadows were so
long. Thanks to the efforts of Fran Ridge of the Lunascan
Project, Mike Lomax, and the espcially to the kind
assistance of the National Space Science Data Center (NSSDC), the
correct frame number, LO2-61H3, was located a few months ago.
Knowing the frame number, we were able to acquire copies of the
8X10 inch black and white negatives directly from NSSDC. Figure 1
below shows the small section of Frame LO2-61H3 containing the
Cuspids and their shadows. The numbers in the photograph reference
five of the objects that will be discussed in more detail here.

Figure 1. The Blair
Cuspids and the Rectangular Trench. This JPEG shows a
section of LO2-61H3 with each pixel 2/3 the size of the smallest
resolvable feature at a 3:1 contrast ratio. A larger GIF version
(345K) with each pixel 1/2 times the smallest resolvable feature can be
downloaded by clicking here

The quality of the negatives is greatly superior to the old
washed-out photographs that have appeared in a few books in
decades past.

With the correct frame number, we were also able to quickly
reference the photographic support data in the Lunar Orbiter 2
catalog to find the angle of sun light illuminating the objects in
the photograh. The catalog data showed that the sun was in the
East at an angle of 79.1 degrees from the lunar vertical, or 10.9
degrees above the lunar horizon. While this sun angle is in fact
low, it is by no means low enough to support the claim that the
shadows were cast by common boulders. From the support data, it
was also determined that this region is located at lunar
coordinates 15.5 degrees East, 5.1 degrees North. In close
proximity to the main group of "Cuspids," is an unusually regular
rectangular depression. The shadow of Cuspid #5, the longest by
far of the Cuspid shadows, falls across this trench and ends
almost at the southern edge of the partially-shadowed interior.

Figure 2. The Trench.
The contrast has been increased by 40% in this image, making the
darker region of the trench nearly black to reveal the unusual
rectangular shape of this depression. The corner of the trench at
the one-o'clock position is an almost unnaturally well-defined
right-angle. When an unusual feature such as this trench is found
in close proximity to other unusual features of an entirely
different kind, such as the "Cuspids", it is reasonable to suppose
that the possibility for an artificial origin of all the features
is substantially increased. This is so because a common geological
explanation is made more difficult and an appeal to improbable
coincidence becomes more necessary to support a natural origin for
the disparate features.

But how different are these Cuspids from garden-variety moon
rocks? What should be a reasonable - albeit tentative and
approximate - reconstruction of the Cuspids' appearance as viewed
in profile is shown in Figure 3 below.

Figure 3. Strange Shapes In Profile. These profile images
are really negative images of the shadows of the 5 objects
indicated by the numbers in Figure
1. The background has been blacked out by hand to
emphasize the overall shape of each object.

In Figure 3, the shadows have been compressed in the direction of
their length according to the simple trigonometric relationship
between an object's height, H, the length of its shadow, Ls, and the tangent of the sun's
elevation angle, A, above the surface on which the shadow falls.
This relationship is:

H = Lstan(A)

Because the first four cuspids appear to be situated on a fairly
horizontal surface, the value of angle A was taken from the NASA
support data to be the sun's elevation above the horizontal, 10.9
degrees and the images of the shadows were compressed by the value
of that angle's tangent, 0.193. A greater compression,
corresponding to a sun angle of 8 degrees (tan(8) = 0.14) was used
for the profile of Cuspid 5 because its shadow falls over the
surface of the rectangular "trench", which is sloping downward
away from the sun, thus effectively decreasing the sun's elevation
above the surface. The
problem of the uncertainty of sun angles and the rationale for
the ones selected for these profile images is discussed at
length here. The detailed contours of the
objects are lost in these profiles due to the irregularities of
the lunar surface and due to the blurring caused by the image
compression algorithm. However, the general shapes of all the
objects except the first can still be clearly be seen to differ
radically from the shapes of common lunar boulders and ridges. The
profiles suggest that Cuspids 2 through 5 have heights greater
than their widths, which would be a very unstable placement for a
randomly placed boulder and even more unusual for a cluster of
them. The hills and ridges of Luna tend to be very low and
rounded. The great lunar mountain Pico Mons in Mare Imbrium, for
example, has a height only 16% of its width. Cuspids 2 though 4
are conical or pyramidal, while Cuspid 5 (still the tallest even
with a lower sun angle assumed) appears to be a cylinder. Based on
the assumption that the sun's elevation is 8 degrees above the
slope on which Cuspid 5's shadow is being cast, the object itself
would have a height of approximately 15 meters or 50 feet. Because
of its large size, Cuspid 5 and its shadow may present a possible
solution to the problem of sun angles and surface slopes, which is
discussed
here.